Consumer safety considerations of cosmetic preservation
Philip A. Geis in Cosmetic Microbiology, 2006
An acute toxicity study involves either a single administration of a test chemical or several administrations within a 24-h period. The animals are then observed for signs of toxicity for a defined period, often 14 days. Most acute toxicity studies are designed to determine the median lethal dose (LD50) of a toxicant. The LD50 has been defined as the median lethal dose of a material that will kill 50% of the animals. Acute studies may also indicate probable target organs and provide guidance on doses to be used in longer duration studies. Important considerations in determining acute toxicity are selection of animal species, route of administration, dosages, number of animals, and environmental factors. All these factors can affect the outcome of a study.
Animal Toxicity Studies
Nicola Loprieno in Alternative Methodologies for the Safety Evaluation of Chemicals in the Cosmetic Industry, 2019
Acute toxicity studies frequently are designed to express the potency of the toxicant in terms of the median lethal dose (LD50), a value representing the estimated dose causing the deaths of 50% of the animals exposed under the defined conditions of the test. In the case of inhalation acute toxicity tests, the toxicant potency is presented as the median lethal concentration (LC50), the estimated concentration in the environment to which the animals are exposed that will result in 50% mortality of the animal population exposed under the defined conditions of the test.
Contrast enhancement agents and radiopharmaceuticals
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha in Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
The LD50 value is a number assigned to a pharmaceutical compound during development stages in clinical trials and relates to the median lethal dose for the substance to kill 50% of the test population. The free gadolinium ion has an LD50 of approximately 100–200 mg/kg, yet the LD50 is increased by a factor of 100 when the gadolinium is chelated. It is important to evaluate every patient and product for potential adverse side-effects before administering the contrast agent.
The impact of exposure route for class-based compounds: a comparative approach of lethal toxicity data in rodent models
Published in Drug and Chemical Toxicology, 2018
Yu Wang, Shuo Wang, Xiao N. Feng, Li C. Yan, Shan S. Zheng, Yue Wang, Yuan H. Zhao
With the ever-growing production of new synthetic chemicals, increased vigilance is needed to identify toxicity risks to humans and wildlife. Toxicity assessments are of primary importance for the safe production and use of both existing chemicals, as well as newly synthesized chemicals. Toxicity tests using rats and mice as models have been widely used to assess the hazard of inorganic and organic chemicals (Zhu et al. 2009, Rasulev et al. 2010, Koleva et al. 2011, Mabrouk et al. 2014, He et al. 2015). An acute toxicity test, expressed as the median lethal dose within a 24-h period to a chemical in a specific exposure route (LD50), for mammals is commonly used in the safety evaluation of chemicals. These acute toxicity data for a chemical in mice and rats can be obtained using different exposure paradigms and several administrations/routes, such as intravenous (i.v.), intraperitoneal (i.p.), subcutaneous (s.c.) and intragastric (i.g.) routes of exposure. There is a wide range of toxicity data available from these different exposure routes (Chui et al. 1988, Sumigama et al. 1994, Mohammad et al. 2006, Wang et al. 2007, 2012), however, this diversity in toxicity testing of chemicals introduces challenges when comparing chemical doses and adverse effects across species.
Preparation of hydroxy genkwanin nanosuspensions and their enhanced antitumor efficacy against breast cancer
Published in Drug Delivery, 2020
Hui Ao, Yijing Li, Haowen Li, Yian Wang, Meihua Han, Yifei Guo, Rongxing Shi, Feng Yue, Xiangtao Wang
It was verified that high dose of HGK-NSps had similar, if not better, antitumor efficacy in comparison with PTX injections (67.8% vs. 61.5%, p > .05, TIR), but there was very significant different in their body weight change (Figure 4(b)). For an antitumor agent, systemic toxicity is another important point to evaluate during tumor treatment. Bodyweight and median lethal dose (LD50) are common indicators for assessing systemic toxicity. The body weight growth curves of the three HGK-NSps groups were close to that of normal saline group while the PTX group showed significant bodyweight reduction after the fourth dose (Figure 4(b)). This indicated HGK-NSps may have better safety than PTX when used in clinic.
Surface modified kokum butter lipid nanoparticles for the brain targeted delivery of nevirapine
Published in Journal of Microencapsulation, 2018
Sunita Lahkar, Malay Kumar Das
The acute toxicity study was carried out as per the Organisation for Economic Co-operation and Development (OECD) guidelines, 423. The Wistar rats in triplicate were administered orally different doses of KB starting from a low dose of 5 mg/kg, 300 mg/kg upto 2000 mg/kg body weight. The animals were kept under daily observation for any sign of toxic effect upto 14 days (OECD guidelines, 423). The LD50 is calculated using the Karber method as given below (Chinedu et al.2013): 50 = Median lethal dose, LD100 = Least dose required to kill 100% population, a = Dose difference, b = Mean mortality, n = Group population.
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